Tsuruta L, Lee H J, Masuda E S, Yokota T, Arai N, Arai K
Department of Molecular and Developmental Biology, University of Tokyo, Japan.
J Allergy Clin Immunol. 1995 Dec;96(6 Pt 2):1126-35. doi: 10.1016/s0091-6749(95)70197-4.
Cyclic adenosine monophosphate (cAMP) inhibits phorbol 12-myristate 13-acetate (PMA)-induced IL-2 production while it inhibits IL-5 production at the transcriptional level in EL-4, a mouse lymphoma line. The -321 to +46 region of the mouse IL-2 promoter is required for activation by PMA and inhibition by cAMP. This promoter region contains several elements that interact with transcription factors, such as nuclear factor of activated T cells (NF-AT), NF-kappa B, AP-1, and octamer. With use of reporter plasmid carrying multiple copies of each element, we found that the construct that contained the NF-AT site was most effective for responding to PMA activation and cAMP inhibition. In electrophoretic mobility shift assay (EMSA), PMA-induced NF-AT binding complex was altered by cAMP. Furthermore, overexpression of the cytoplasmic component of NF-AT abrogated the inhibitory action of cAMP. These results indicate that the NF-AT site is a target of the inhibitory action of cAMP. We have previously reported that the -1200 to +33 region of the mouse IL-5 promoter can mediate transcriptional stimulation by PMA and cAMP in EL-4 cells. Here we identified the element IL-5P, which is required for maximal activation of the IL-5 promoter. We found that this element is homologous to the binding site for NF-AT and interacted with NF-AT-related factors induced by PMA and cAMP. Thus it appears that an NF-AT factor is involved in the regulation of IL-5 gene transcription.
环磷酸腺苷（cAMP）可抑制佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）诱导的白细胞介素-2（IL-2）生成，同时在小鼠淋巴瘤细胞系EL-4中，它在转录水平抑制IL-5的生成。小鼠IL-2启动子的-321至+46区域是PMA激活和cAMP抑制所必需的。该启动子区域包含多个与转录因子相互作用的元件，如活化T细胞核因子（NF-AT）、核因子κB（NF-κB）、活化蛋白-1（AP-1）和八聚体。通过使用携带每个元件多个拷贝的报告质粒，我们发现含有NF-AT位点的构建体对PMA激活和cAMP抑制的反应最为有效。在电泳迁移率变动分析（EMSA）中，cAMP改变了PMA诱导的NF-AT结合复合物。此外，NF-AT细胞质成分的过表达消除了cAMP的抑制作用。这些结果表明，NF-AT位点是cAMP抑制作用的靶点。我们之前报道过，小鼠IL-5启动子的-1200至+33区域可介导EL-4细胞中PMA和cAMP的转录刺激作用。在此我们鉴定出了元件IL-5P，它是IL-5启动子最大激活所必需的。我们发现该元件与NF-AT的结合位点同源，并与PMA和cAMP诱导的NF-AT相关因子相互作用。因此，似乎NF-AT因子参与了IL-5基因转录的调控。
